Alkanol gels



United States Patent Ofiice 3,342,569 Patented Sept. 19, 1967 3,342,569 ALKANOL GELS Garland George Corey, Milltown, and Edward Joseph Kenney, Bernardsville, N.J., assignors to Colgate- Palrnolive Company, New York, N.Y., a corporation of Delaware No Drawing. Filed Nov. 18, 1963, Ser. No. 324,246 9 Claims. (Cl. 44-7) The present invention relates to new compositions of matter and, more particularly, to novel stable gels comprising one or more alcohols, nitrocellulose gelling agent, and a gel-stabilizing agent comprising those hydrophilichydrophobic polyoxypropylene polyoxyethylene glycols which contain fifty percent or more polyoxypropylene groups and fifty percent or less polyoxyethylene groups. Or in other words, hydrophilic hydrophobic polyoxypropylene polyoxyethylene glycols in which the polyoxypropylene groups are at least fifty percent of the substituent groups and the polyoxyethylene groups are the balance of the substituent groups.

Although alcohol-water mixtures have been gelled for about fifty years by the use of nitrocellulose as the gelling agent for use as solidified fuels, the available solidified alcohol-water fuels have not been completely satisfactory. Thus, prior art gels tend to form with a large number of relatively large pockets of the flammable liquid which, during storage, tend to release the flammable fluid with a liquid separation of the gel. In other words, previously available solid fuel gels are subject to syneresis. Solidified alcohol-water fuels to be acceptable to the trade have the following characteristics, to wit: (1) a smooth surface, (2) the gel must be firm or substantially rigid so that the gel structure does not break down during shipment, (3) two hundred grams of the gel must burn for approximately two hours, (4) the gel must have a minimum heating value of approximately 7000 B.t.u. per pound (7000 B.t.u./lb.), (5) they must burn without producing any substantial amount of soot, except in those instances where conditions surrounding the use thereof make a luminous flame desirable, (6) two hundred grams of the gel must leave substantially no residue after burning, and (7) most important the gel must not be subject to syneresis, i.e., little or no liquid bleeds from the gel during storage at a temperature in the range of 75 to 100 F. While it is advantageous to use anhydrous alcohols as the solvent for the nitrocellulose, a diluent such as water can be present in the alcohol in a concentration which does not lengthen the time required to dissolve the nitrocellulose to an industrially impractical degree or prohibit solution of the nitrocellulose.

In accordance with the present invention a stable alcohol gel comprises at least one alcohol, a nitrocellulose gelling agent in amounts sulficient to produce a firm, substantially non-macroporous, gel of said alcohol and water and a gel-stabilizing agent comprising one or more Pluronics. Furthermore, a stable alcohol gel comprises one or more alcohols, another combustible solvent, a nitrocellulose gelling agent in amount suflicient to produce a firm, substantially non-macroporous, gel of said alcohol, other combustible fuel and water, and a gel-stabilizing agent comprising one or more Pluronics.

Alcohols which can be employed in preparing the new compositions of the present invention include monohydroxyalcohols which exhibit the required properties of combustibility and form the aforesaid firm, substantially non-macroporous gels when gelled by the addition of nitrocellulose. Accordingly, the term alcohol as employed herein and in the appended claims is to be understood to include any monohydroxyalcohol which forms a gel of the desired viscosity with water and nitrocellulose, which gel burns with heat of acceptable intensity and leaves little residue after burning. Such compounds are the aliphatic alcohols having one to four carbon atoms in the molecule such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol. When the requirements pertaining to the amount of soot produced are less stringent as, for example, when a luminous flame is desired, higher molecular weight monohydroxyalcohols can be used provided they are used in concentrations which do not impair the basic requirements of a solid fuel, form a stable gel with the nitrocellulose gelling agent and the Pluronics" stabilizing agent, and have the desired combustibility to suit the paricular use.

In order to dissolve the nitrocellulose it is preferred to use anhydrous or nearly anhydrous alcohol, e.g., alcohol containing not more than one or two percent of water to form the sol which is then converted to a gel by the addition of water. Generally, it is preferred that the gels of the novel fuel-gel compositions of the present invention contain at least seventy percent of alcohol when the diluent is water providing a gel having a heating value of about 9400 B.t.u.

Although excellent fuel-gel compositions are made by using a single alcohol such as methanol or ethanol or propanol, a mixture of two or more alcohols can be utilized. When such is the case, the mixture of alcohols can be in any proportion as long as the total alcoholic content of the gel is sufficient to provide acceptable properties of combustibility. An excellent fuel-gel can be prepared which gel burns with a substantially smokeless and sootfree flame when a mixture of ethanol and methanol is used and the methanol is present in an amount of about forty percent by weight, based on the total weight of the composition.

When the requirements relating to the production of soot are less stringent, other combustible fuels, for example, hydrocarbons such as benzol, gasoline, mineral spirits and certain oxygenated compounds, such as ketones having up to six carbon atoms, e.g., acetone, methylethyl ketone, and the like although the production of soot will be to an undesirable degree for some purposes. When sooting is a stringent limitation, ketones having not more than three or four carbon atoms can be used. While the ketones have been considered hereinbefore as auxiliary fuels, the lower ketones such as acetone and methyl-ethyl ketone are primarily solvent boosters or solvents for the nitrocellulose. Accordingly, the ketones, especially the ketones having three and four carbon atoms, are considered to be auxiliary solvents rather than auxiliary fuels. Since the other combustible fuels, benzol, gasoline and the like are non-polar in nature and tend to separate from the remainder of the composition, they are usually present in relatively small amounts, preferably up to about ten percent by weight of the composition although this limitation is not critical. Greater amounts of the non-polar compound(s) can be present provided the stability and combustibility of the final composition is not adversely af- 3 4 fected. Thus, the preferred ketones can be present as sol- Component: Weight percent vents to the extent of five to ten percent while the auxil- Base mix 67.683 iary fuels can be used in amounts up to ten percent of Anhydrous ethanol 32.314 the composition of the sol. Denaturant and dye 0.003

The gelling agent is nitrocellulose having a nitrogen 5 concentration in the preferred range of 11.5 to 12.5 per- 100.000 cent 1 Specially denatured ethyl alcohol.

The stabilizing agent, i.e., Pluronics is described in F h fi i h d ll di i h fue1- 1 PatCHt No. The anufa turer of Pluposition is made to have the composition given hereinl'OIllCS defines the materials PlUIOl'llC L-64 and Plll- 1O befgre, Thus composition A was prepargd by adding Ionic" L-92 as polyoxypropylene polyoxyethylene polyanhydrous methanol and Pluronic L64 to the finished mers having the generic formula collodion" mix and then gelling the collodion mix by shocking by the flddlllOIl Of water.

The manufacturer, Wyandotte Chemical Company, Fuel'gel h states that Pluronics" L-64 and L-9'2 are prepared by Component We1g t percent adding propylene oxide to the two hydroxyl groups of a l lf collodiin propylene glycol nucleus. The resulting hydrophobic base y 91 igi, am can be made to any controlled length. By adding ethylene W uromc. oxide to both ends of the hydrophobic base, it is possible (my) to put polyoxyethylene hydrophobic groups on the end 0 00 of the molecule. When the polyoxypropylene polymer 10 is the polyoxypropylene glycol having a molecular weight Exemplary of the buring characteristics of a fuel-gel of at least 900 and ethylene oxide is condensed therewith having a composition such as that of Examples A and in an amount constituting twenty to ninety percent of B are the following data:

TABLE I Grams Pluronie Water, Burning Maximum Fuel-Gel L-64, Percent Percent Time, Temperature, Resldue Burned Weight Weight Minutes F.

200 0 21 140 168 No detrimental residue. 200 33 21 135 167 Do. 200 0 24 123 169 Do.

1 Temperature of 3,500 ml. of water being heated by the 200 g. sample.

the resultant compound the subscripts in the foregoing TABLE IA formula have the followmg values: [Nitrocellulose-2 percent by weight. Sample-680 gram samples] m has a value such that the oxyethylene groups constitute 20-90%, by weight, of the compound, and sample No. gfg zffggg 2:2 2512; n 15 a whole number IP64 Liquid Other Pluronics" that can be used include Pluronics" 21 79 0 14 B L-64, L62, P-75, L92, L-l03 and in general, those 2. 21 78.7 0 s 14 4 polyoxypropylene polyoxyethylene glycols which contain 24 0 3 14 4 fifty percent or more polyoxypropylene groups and fifty Mm d b in of n d ihi t sure our Ice 11] an We 11 m0 percent or less polyoxyethylene groups. Or in otherwords, free liquid is a i'n asure oi the syni'esis oi the gil. 1% will obs e r ve d polyoxypropylene polyoxyethylene glycols 1n WlllCh the that1 the Eamount at freeliquicl in samples Nos.2aud3isonly fifty percent polyoxypropylene groups are at least fifty percent of the 0 t at Examp e substituent groups and the polyoxyethylene groups are Exemplary 0f fuel-gels contalnlng a fuel other than an th b l of h b tit t groups alkanol is a fuel-gel with about three percent of acetone.

Illustrative of a fuel-gel composition comprising two A base mix having the following compositionls P P alcohols as the combustible fuel, nitrocellulose as the mponent: We1ght percent gelling agent, and Pluronic L-64 as the gel-stabilizing P y ethanol 1 82403 or anti-syneresis agent are the following compositions. Nitrocellulose 2 3-232 Acetone 9.36 5 We1ght percent Component: A B 100.000

i ll l 1,918 1,827 1 Spe y denatured t y o o Methanol 56.335 54.464 jg gg ggr gggggat 122% 122% fi i l: g gg g A finished collodion mix is prepared from the base l Pluronic IP64 0.330 0300 mix to have the 0 lowing composition. Water 20.000 23.000 p Weight percent I 65 Base mlx 43.378 1 S ecially denatured ethyl al oh l. Anhydrous ethanol 1 36.616 The gel-fuel is prepared from a base mix containing: Ethanol 2 20.000 Percent Denaturant and dye 0.006 Methyl alcohol 93.650 Nitrocellulose 2 6.350 100000 1 Specially denatured ethyl alcohol. =Nitroge2n50e(%nt3(t)116g; to 12.2%. Viscosity of 12.2% 2 Specially denatured ethyl alcohol. solution.- 0 Sec Pluronic L-92 is dissolved in the finished collodion From the base mix a fimshed collodion IIllX is premiX and the gel precipitated, i.e., shocked by the addition pared having the following composition. of water to give a final fuel-gel composition as follows.

6 Component: Weight percent Gel C Nitrocellulose 1.992 Component: Weight percent Acetone 3.237 Ethanol 71.1 to 65.7 Ethanol 69.315 Methanol 3.6 to 3.3 Dye and denaturant 0.004 5 Acetone 3.3 to 3.1 Pluronic" L-92 0.300 Solids (nitrocellulose) 2.0 to 1.9 Water 25.152 Water 20.0 to 26.0

TABLE II [Gel containing 21 percent of water] Grams of Percent Days at Grams Percent Days at Grams Percent Sample No. Sample "Pluronlc 78 1*. Free of Sample 120 F. Free of Sample L-92 Liquid Liquid TABLE III [Gel containing 23-24 percent of water] Grams of Percent Days at Grams Percent Days at Grams Percent Sample N 0. Sample Pluronic 78 F. Free of Sample 120 F. Free of Sample n02" Liquid Liquid 1 680 0 12 1. 76 4 as s. 53 2 080 0 125 14 2.06 3. 680 0. 3 42 s 0. 44 4 so 7. 35 680 0.3 125 10 1.47 680 0. 5 42 5-0 0. s0 4 38 s. 00 630 0. 5 125 1-2 0. 22

TABLE Iv [Gel containing 25-26 percent of water] Grams of Percent Days at Grams Percent Days at Grams Percent Sample No. Sample Pluronic 78 F. Free of Sample 120 F. Free of Sample L-92" Liquid Liquid 680 0 42 s 1.18 1 48 7.00 680 0 125 9 1. 32 680 0.3 42 5 0. 73 4 37 5.41 080 0. 3 125 2-3 0. 37 4 14 2. 04 680 0.2 20 4 0.58 4 17 2. 4a 680 0. 1 20 5 0. 73 4 38 5. 55 680 0.5 4 9 1.32 680 1.0 Other fuel-gels having compositions as set forth here- Even cursory examination of the data presented in inafter have been prepared in a similar manner. Tables II, III and IV establishes that 0.1 percent of I Pluronic is sufficient to reduce the syneresis of a nit-ro- Component: Weight percent cellulose-alcohol-water gel a practical amount. On the Nitrocellulose 1.867 1.8 7 other hand, an amount of Pluronic L-92" in excess of Acetone 3.034 3.038 0.5 percent, for example, one percent, converts the gel Ethanol 67.965 68-0 4 from a firm gel to a mush. Thus, the use of concentrations Dye and denaturant 0.005 0.005 in excess of 0.5 gel percent is not recommended. Plur0nic" L-92 0.300 0.200 From the foregoing description of the present inven- Water 26.829 26.836 tion those skilled in the art will recognize that the present invention provides a stable composition comprising one 100.000 100.000 or more alcohols as the major component, a nitrocellulose gelling agent in amount sufficient to form a gel say he marked r dll ct n 1 syner sis as u d y the about one to about three percent, about 15 to 30 percent grams of frfie liquld after g g a r m temperature of water, and about 0.1 to about 0.5 percent of Pluronic (78 F.) and after accelerated aging at 120 F. 15 1005- L-64, Plu ronic P-75, Pluronic L-62, Pluronic L trated by the data presented in Tables II, III and IV herc- 92, Pluronic L-103 or in general a hydrophilic-hydroinafter. Three gels containing respectively, A"-20 to 5 phobic polyoxyalkylene-polyoxypropylene in which the 21 percent of water; B23 to 24 percent of water and polyoxypropylcne moiety has a molecular weight of at C25 to 26 percent of water were prepared. Comleast 900 and constitutes about 50 to about 90 percent parisons of the amount of free liquid after storage of these of the compound. Those skilled in the art will understand gels free from a Pluronic" and containing the indicated that non-polar fuels in amounts up to about 10 percent amount of P-luronic L-92 is provided in Tables II, III can be included in the mixture and that denaturants, dyes, and IV, and odorants also can be admixed with the basic com- The gels employed for illustrating the effect of Pluponents of the mixture. Ionics" upon syneresis of nitrocellulose gels had composi- What is claimed is: tions within the set forth hereinafter and differed only by 1. A stable alcohol gel composition comprising a major the concentration of water. Proportion of at least one aliphatic monohydroxy alcohol,

a minor proportion, sufiicient to form a gel with said alcohol, of nitrocellulose, about 15 to about 30 percent of water, and about 0.2 to 1.0 percent of at least one hydrophillic-hydrophobic polyoxyalkylene polyoxypropylene in which the polyoxypropylene moiety has a molecular weight of at least 900 and constitutes about 50 to 90 percent of the said polyoxyalkylene polyoxypropylene.

2. An alcohol gel composition as set forth in claim 1 wherein the alcohol constitutes about 65 to about 80 percent of the total weight of the composition.

3. An alcohol gel composition as set forth in claim 1 wherein the alcohol constitutes about 65 to 80 percent of the total weight of the composition and the alcohol has one to four carbon atoms in the molecule.

4. An alcohol gel composition as set forth in claim 1 containing up to about 10 percent of at least one of an auxiliary fuel and a ketone having not more than six carbon atoms.

5. An alcohol gel composition as set forth in claim 1 containing up to about ten percent of acetone.

6. An alcohol gel composition as set forth in claim 1 containing up to about ten percent of an auxiliary fuel selected from the group consisting of benzol, gasoline, and mineral spirits.

7. An alcohol gel composition comprising Component: Weight percent Aliphatic alcohol having 1 to 4 carbon atoms 66.5 to 82.9 Nitrocellulose (11 to 13% nitrogen) 2.5 to 1.9 Water 30.0 to 15.0 Polyoxypropylene polyoxyethylene 1.0 to 0.1 Dyes, denaturants, odorants-Balance to make 100%.

8. A stable alcohol gel composition comprising by weight about 56.5 to 77.3 percent of at least one aliphatic monohyd'roxy alcohol, about 1.5 to 2.5 percent of nitrocellulose containing 11 to 13 percent nitrogen, about 20 to 30 percent water, about 0.1 to 0.5 percent of at least one hydrophilic-hydrophobic polyoxyalkylene polyoxypylene in which the polyoxypropylene moiety has a molecular weight of at least 900 and constitutes about to percent of the said polyoxyalkylene polyoxypropylene, about 1 to 10 percent of an auxiliary fuel and ketone, and the balance of the composition to make percent being dyes, denaturants and odorants.

9. An alcohol gel composition as set forth in claim 8 wherein the ketone is acetone.

References Cited UNITED STATES PATENTS 2,504,196 4/1950 Holmes 447 2,613,142 10/1952 Wiczer 447 3,072,467 1/1963 Wiczer 44-7 FOREIGN PATENTS 841,738 7/ 1960 Great Britain.

OTHER REFERENCES Pluronics," Wyandotte Chemicals Corporation, Wyandotte, Mich. (Recd in Scientific Library, Jan. 7, 1957).

DANIEL E. WYMAN, Primary Examiner.

C. F. DEES, Assistant Examiner. 

1. A STABLE ALCOHOL GEL COMPOSITION COMPRISING A MAJOR PROPORTION OF AT LEAST ONE ALIPHATIC MONOHYDROXY ALCOHOL, A MINOR PROPORTION, SUFFICIENT TO FORM A GEL WITH SAID ALCOHOL, OF NITROCELLULOSE, ABOUT 15 TO ABOUT 30 PERCENT OF WATER, AND ABOUT 0.2 TO 1.0 PERCENT OF AT LEAST ONE HYDROPHILLIC-HYDROPHOBIC POLYOXYALKYLENE POLYOXYPROPYLENE IN WHICH THE POLYOXYPROPYLENE MOIETY HAS A MOLECULAR WEIGHT OF AT LEAST 900 AND CONSTITUTES ABOUT 50 TO 90 PERCENT OF THE SAID POLYOXYALKYLENE POLYOXYPROPYLENE. 